Water flooding is a conventional process of enhancing the extraction of hydrocarbon materials (e.g., crude oil, natural gas, etc.) from subterranean formations. In this process, an aqueous fluid (e.g., water, brine, etc.) is injected into the subterranean formation through injection wells to sweep a hydrocarbon material contained within interstitial spaces (e.g., pores, cracks, fractures, channels, etc.) of the subterranean formation toward production wells offset from the injection wells. One or more additives may be added to the aqueous fluid to assist in the extraction and subsequent processing of the hydrocarbon material.
For example, in some approaches, a surfactant, solid particles (e.g., colloids), or both are added to the aqueous fluid. The surfactant and/or the solid particles can adhere to or gather at interfaces between a hydrocarbon material and an aqueous material to form a stabilized emulsion of one of the hydrocarbon material and the aqueous material dispersed in the other of the hydrocarbon material and the aqueous material. Surfactants may decrease the surface tension between the hydrocarbon phase and the water phase, such as, for example, in an emulsion of a hydrocarbon phase dispersed within an aqueous phase. Stabilization by the surfactant, the solid particles, or both, lowers the interfacial tension between the hydrocarbon and water and reduces the energy of the system, preventing the dispersed material (e.g., the hydrocarbon material, or the aqueous material) from coalescing, and maintaining the one material dispersed as units (e.g., droplets) throughout the other material. Reducing the surface tension increases the permeability and the flowability of the hydrocarbon material. As a consequence, the hydrocarbon material may be more easily transported through and extracted from the subterranean formation as compared to water flooding processes that do not employ the addition of a surfactant and/or solid particles. The effectiveness of the emulsion is determined in large part by the ability of the emulsion to remain stable and ensure mixing of the two phases.
However, application of surfactants is usually limited by the cost of the chemicals and their adsorption and loss onto the rock of the hydrocarbon-containing formation. Disadvantageously, the affectivity of various surfactants can be detrimentally reduced in the presence of dissolved salts (e.g., such as various salts typically present within a subterranean formation). In addition, surfactants can have a tendency to adhere to surfaces of the subterranean formation, requiring the economically undesirable addition of more surfactant to the injected aqueous fluid to account for such losses. Solid particles can be difficult to remove from the stabilized emulsion during subsequent processing, preventing the hydrocarbon material and the aqueous material thereof from coalescing into distinct, immiscible components, and greatly inhibiting the separate collection of the hydrocarbon material. Furthermore, the surfactants are often functional or stable only within particular temperature ranges and may lose functionality at elevated temperatures or various conditions encountered within a subterranean formation.